Observation of the Josephson effect in Pb/(Ba,K)Fe2As2 single crystal junctions

Abstract

We have fabricated c-axis Josephson junctions on single crystals of (Ba,K)Fe2As2 by using Pb as the counter electrode in two geometries, planar and point contact. Junctions in both geometries show resistively shunted junction I-V curves below the Tc of the counter electrode. Microwave induced steps were observed in the I-V curves, and the critical currents are suppressed with an in-plane magnetic field in a manner consistent with the small junction limit. ICRN products of up to 0.3 mV have been observed in these junctions at 4.2 K. The observation of Josephson coupling along the c-axis between (Ba,K)Fe2As2 and a conventional superconductor suggests the existence of a s-wave superconducting order parameter in this class of iron pnictide superconductors.

16 pages and 3 figures

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• Three-band superconductivity and the order parameter that breaks time-reversal symmetry
• Functional Renormalization Group for multi-orbital Fermi Surface Instabilities
• Integer and half-integer flux-quantum transitions in a niobium/iron-pnictide loop
• Second-order Topological Superconductors with Mixed Pairing
• Anisotropic Structure of the Order Parameter in FeSe0.45Te0.55 Revealed by Angle Resolved Specific Heat
• Josephson junction in cobalt-doped BaFe2As2 epitaxial thin films on (La, Sr)(Al, Ta)O3 bicrystal substrates
• London penetration depth in Ba(Fe${}_{1-x}$T${}_x$)${}_2$As${}_2$ (T=Co, Ni) superconductors irradiated with heavy ions
• Possible phase-sensitive tests of pairing symmetry in pnictide superconductors
• Thin Film Growth and Device Fabrication of Iron-Based Superconductors
• Calorimetric Evidence of Strong-Coupling Multiband Superconductivity in Fe(Te0.57Se0.43) Single Crystal
• BaFe_{1.8}Co_{0.2}As_2 thin film hybrid Josephson junctions
• Raman scattering study of Spin-Density-Wave order and electron-phonon coupling in Ba(Fe${}_{1-x}$Co${}_x$)${}_2$As${}_2$
• Josephson effect between a two-band superconductor with the s++ or s+- pairing symmetry and a conventional s-wave superconductor
• Impurities in multiband superconductors
• $\pi$-junction to probe antiphase s-wave pairing in iron pnictide superconductors
• Designing phase-sensitive tests for Fe-based superconductors
• Entangled Orbital Triplet Pairs in Iron-Based Superconductors
• Ambegaokar-Baratoff relations of Josephson critical current in heterojunctions with multi-gap superconductors
• Proximity and Josephson effects in microstructures based on multiband superconductors
• Josephson effect between electron-doped and hole-doped iron pnictide single crystals
• Anisotropic vortex lattice structures in the FeSe superconductor
• C-axis critical current of a PrFeAsO0.7 single crystal
• Evidence of a universal and isotropic 2Δ/kBTC ratio in 122-type iron pnictide superconductors over a wide doping range
• Josephson Effects in Three-Band Superconductors with Broken Time-Reversal Symmetry
• Metastable $\pi$-junction between an s${}_{\pm }$-wave and an s-wave superconductor
• Shapiro Steps as a Direct Probe of $\pm s$-wave Symmetry in Multi-gap Superconducting Josephson Junctions
• Jc Scaling and Anisotropies in Co-doped Ba-122 thin films
• Microstructure and superconductivity of Ir-doped BaFe2As2 superconductor
• Quasiclassical description of a superconductor with a spin density wave
• Investigation of TiO${}_x$ barriers for their use in hybrid Josephson and tunnelling junctions based on Ba-122 thin films
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• Macroscopic quantum tunneling in multigap superconducting Josephson junctions: Escape rate enhancement via quantum fluctuations of Josephson-Leggett mode
• TAO pairing: a fully gapped pairing scenario for the Iron-Based Superconductors
• Probing the Order Parameter of Superconducting LiFeAs using Pb/LiFeAs and Au/LiFeAs Point-Contact Spectroscopy
• Evolution of the Fermi surface topology in doped 122 iron pnictides
• Anomalous Tail Effect on Resistivity Transition and Weak-link Behavior of Iron Based Superconductor
• Possible pi-phase shift at interface of two pnictides with antiphase s-wave pairing
• The microscopic basis for phase-sensitive experiments for determination of the order parameter symmetry in Fe-based superconductors
• Design and construction of a point-contact spectroscopy rig with lateral scanning capability
• Josephson effect and Andreev reflection in Ba(1-x)NaxFe2As2 (x=0.25 and 0.35) point contacts
• Evolution of quasiparticle states with and without a Zn-impurity in doped 122 iron pnictides
• Effects of order parameter self-consistency in a $s_{\pm }$-s junction